Brake lining condition inditor system

ABSTRACT

A brake lining condition indicator system having an electrical contact formed of an insulating sleeve attached to the brake lining support and containing a conducting rod extending into the underside of the brake lining and having an electrical display device and power source connected to such contact so that when the brake lining wears down and the braking surface contacts such rods the display device is activated.

. unitedsteees Patent [e1 Gorgie et al BRAKELINING CONDITION INDITOR SYSTEM Inventors: Frank J. Gorgie,"98l2 La Cresta '1 Circle, .Huntin gton Beach, Calif.

92627; Gene A. Johnson, 2244131151 FranzemSanta Ana, Calif. 92705 Filed: April 5,1911

Appl. No.2 131,1s1'

0.5. 0.... .;...;...340/s2 A, ZOO/61.4 Int. Cl. ..B60t 17/22 Field 01 Search .340 52 R, 53 200/6l.4, 6l.4l,200/61.44

References Cited UNITEDFSTATESPA T EN TS 2,814,684 11/1957 De Pascale ...340/52A 14 1 Feb. 13, 1973 4/1961 Rizzoetal....... ..'.340/52A 8/1968 Linet ..340/52AX Primary Examiner -Alvin H.- Waring Attorney-William A. Kemmel, Jr. I

[57] ABSTRACT A brake lining condition indicator system having an electrical contact formed of an. insulating sleeve attached to the brake lining support and containing a 1 Claim, 3 DrawingFlgures PATENTED FEB-1 3197s Fig. 3.

Frank J. G e, Gene A. Jo on,

INVENTORS.

ATTORNEY.

BRAKELINING CONDITION INDITOR SYSTEM I BACKGROUND OF'THE INVENTION It is well recognized by most vehicle owners or operators that proper maintenance of the brake systemincluding particularly insuring that the brake lining does not become too worn is an important part of proper care of the automobile. For example, if the automobile is operated with worn out brake linings, at the very least when such condition is discovered substantial repair .costs are encountered. More important, such situation can caus'ea'brake failurewhich could result in serious accidentcausing personal injury or substantial damage. Consequently, [most vehicle owners and .operators are aware that their :braking'system main tenance includes-periodic replacement of the brake linings'but to date there'has been no adequate system periodic warningshavenot been accepted.

Because of; the importance of determining when brakes should be relined and the .lack of satisfactory system for making such determination, a substantial number of systems have been proposed to make. such determination; :however, none of such systems have foundsignificant acceptance to date. One reason for such lack of acceptance is that systemsproposed to date have ,not been sufficiently reliable in that they sense only indirectly the-extent of wear on the brake lining and thus are frequently affected by other factors. I Also, such systemsproposed to date, have been relatively expensive, difficult to install and burdensome to maintain. For example,=theyusuallycannot be easily installed on used vehicles.

Consequently, an object of thep'resent invention is an inexpensive brake lining condition indicator system adapte'd-tobe-easily installed in eitherused or new vehicles or other equipment having abrakesystem.

Another object of-the present invention is a brake lining'condition indicator "system which senses directly the wear of thebrakelining below a'selected thickness.

Still another object of v the present invention is a brake liningcondition indicator system adapted to use the normal power supplyof a vehicle toprovide a visual indication "when the brake lining becomes too worn each time the brake=system is used so that thereis a constant reminderthat brake relining is required.

Other, objects and advantages of the present invention. will be'readily apparent from the following description and drawings which illustrate a preferred exemplaryembodiment of the present invention.

SUMMARY OF THE INVENTION In general, thepres'ent inventioninvolves a brake lining condition indicator system comprising electrical available to determine when such relining should be contact means adapted to be attached to the brake lining support structure including an electrically conducting rod and an electrically insulating sleeve attached to such rod and separating such rod from the'brake lining support structure. The inner end of the rodextending a selected distance into theunderside of the brake lining.

Also the brake lining condition indicatorsystem includes a display means electrically connected to such rod and a powersupply adapted to activate such display means when the brake surface contacts the rod after sufficient wearing down of the brake lining.

In order to facilitate understanding of the present invention, reference will now be made to appended drawings of a preferred specific embodiment of the present invention.- Similar to the summary of present invention, such drawings should not be construed as limiting the present invention which is properly set forth in the appended claims.

DESCRIPTION OF DRAWINGS DESCRIPTION OF THE PREFERRED I EMBODIMENT O THE.

PRESENT INVENTION As illustrated in FIGS. 1-3 of the brake lining condition indicator system 10is adapted to sense directly the wear of a brake lining 11 mounted on a support structure 12 such as a brake shoe below a selected thickness indicated by the depth of the pocket 13 in the brake lining 11 byan electrically conducting brake surface 14 of a reference structure 15 such asa brake drum. The

brake lining condition indicator system 10 comprises an electrical contact means 20 adapted to be attached to the brake lining support structure 12, a display means 40 and a power supply 50. The electrical contact means 20 includes an electrically conducting rod 21 and an electrically insulating sleeve 20 attached to the rod 21 and separating the rod 21 fromthe brake lining support structure 12. The inner end 22 of the rod 21 extends a selected distance into the underside 16 of the brake lining 11 and has ataperedtip 23 adapted to improve electrical contact with -'the braking surface 14 and to accurately determine the selected thickness of the brake lining. The outer end 24 of the rod 21 has a head 25 adapted to set the distance the rod 21 extends into the underside 16 of the brakelining 11. Thus the location of the shoulder 26 of the rod he ad25 determine the effective length to the tip 23 of the rod 21. Preferably the rod 21 has a uniform external diameter except for the tip23 and the head 25 and. is formed of an electrically conducting material such as copper, aluminum, and brass. In addition to being electrically conducting, such material shouldbe relatively softso that simply makes electrical contact therewith.

trated, the inner end 31 of the sleeve 30 has a substantially uniform internal diameter slightly larger than the diameter of the rod 21 so that the rod 21 is slidably received therein. The outer end 32 of the sleeve 30 has a recess 33 adapted to receive the head 25 of rod 21.

Thus the recess 33forms a seat 34'which receives the shoulder 26 of the rod 21 and thereby cooperates in setting the distance the rod 21 extends into the understructure 12. The sleeve 30 is made of an electrically insulating material such asceramic, glass, and plastic.

Attached to the head 25 of the rod 21 and'extending out of the recess 33 of the sleeve 30 is an electrical conductor 35 such as a. metal wire which is connected through thedisplay means 40 to thepower supply 50, such as a grounded car battery. Holding the rod 21 in the sleeve '30 is aplastic plug 36'. The display means 40 and the power supply 50 as noted above, is electrically connected to the rod 21 by electrical conductor 35. Display means 40-are preferably simply-a light source such as an incandescent bulb which is activated by the passage of electrical current therethrough and which is locatedin the vehicle so as to be visible to the vehicle operator. The power supply 50 is preferably simply the car battery; however any other conveniently available power supply connected to the vehicle may be utilized. The power supply 50 is adapted to activate the display means 40 when the brake surface 14 contacts the tip 23 of the rod 21 after sufficient wearing down of the brake lining 11.

' The operation of the brake lining condition indicator system l'is adapted to directly sense the wear of the brakev liningbelow a selected thickness. Thus, after the brake lining 11 is worn down so that the braking surface 14, such as the internal surface of a brake drum contacts the tip 23 of the rod 21, an electrical circuit is thereby completed since the brake drum is an effective ground. Once such circuit is completed, current flows from thepower source 50 through the display means 40 which activates the display means thereby is a visual indicati on to the operator of the vehicle that the brake lining needs replacement. Such signal is, of course, repeatedeachtime the vehicle operator uses the brakes so that there is a constant reminder of the need for relining the brakes.

it will be appreciated that many other specific embodiments of the present invention will be obvious to one skilled in the arts in view of the disclosure of the preferred embodiment of the. proposed invention. For example, if desired, a separate display means could be utilized for each brake lining or any group of brake linings as wellas all of the brake linings so that detailed information about individual brake linings could be obtained. Likewise, various configurations of either the rod orthe sleeve or-both could be utilized in the contact means to sense the wearing of the brakelining by the conducting portion thereof while insulating such conducting portion from the brake lining support structure to which it is conveniently attached. Also, the inner end of the sleeve may have one standard length which can be varied for specific brake 'systemsby adding a selected number of washers vof selected thickness. Of course, if the brake lining support structure were made of insulating material the sleeve could be eliminated since its function would inherently be performed by such structure. Similarly the rod could be reduced in diameter so that it is simply a wire which protrudes into the underside of the brake lining; however, all "of such variations are considered to be equivalent to the claimed structure. Moreover the brake lining condition system of the present invention is of course not limited to vehicles such as automobiles, trucks and buses but also can be used in disc brake systems as well as any equipment which uses comparable brake systems.

There are many features in the present invention which clearly show a significant advance which the present invention achieves over the prior art. Con sequently, only a few of the more outstanding features will be pointed out to illustrate the unexpected and unusual results obtained by the present invention. One feature of the present invention is that the brake lining condition indicator system senses directly the wear of the brake lining and thus gives an accurate indication of such wear independent of such variables as the driving conditions, and the driving habits of the vehicle operator. Another feature of the present invention is its simplicity and ease of installation since presently existing portions of the vehicle may be utilized such as the battery for the power supply and thebraking surface for the electrical ground. Thus the system of the present invention cannot only be easily installed in new vehicles but also in presently used vehicles. Moreover,

such simplicity permits the present invention to be both inexpensive and achieve a high degree of reliability which is in marked contrast to the prior art systems. Still another feature of the present invention is the soft fine tip of the contact rod which permits accurate setting of the brake lining thickness and prevents damage to the brake surface.

It will be understood that the foregoing description drawings are only illustrative of the present invention and it is not intended that the invention be limited thereto. All substitutions, alterations and modifications of the present inventions which come within the scope of the following claims or to which the present invention is readily susceptible without departing from the spirit and scope of this disclosure are considered part of the present invention.

We claim:

1. An inexpensive, easily installed brake lining condition indicator system adapted to sense directly the wear of the brake lining below a selected thickness by an electrically conducting brake surface comprising (a) contact means adapted to be attached to the brake lining support structure including an electrically conducting rod and an electrically insulating sleeve attached to said rod and separating said rod from the brake lining support structure, the inner end of said rod extending a selected distance into the underside of the brake lining and the inner end of said sleeve is adapted to receive said rod and the outer end of said sleeve has a recess adapted toreceive said rod head and set the distance said rod extends into the underside of the brake lining, (b) display means directly connected to said rod, and (c) a power supply adapted to activate said display means when the brake surface contacts said rod after sufficient wearing down of the brake lining. 

1. An inexpensive, easily installed brake lining condition indicator system adapted to sense directly the wear of the brake lining below a selected thickness by an electrically conducting brake surface comprising (a) contact means adapted to be attached to the brake lining support structure including an electrically conducting rod and an electrically insulating sleeve attached to said rod and separating said rod from the brake lining support structure, the inner end of said rod extending a selected distance into the underside of the brake lining and the inner end of said sleeve is adapted to receive said rod and the outer end of said sleeve has a recess adapted to receive said rod head and set the distance said rod extends into the underside of the brake lining, (b) display means directly connected to said rod, and (c) a power supply adapted to activate said display means when the brake surface contacts said rod after sufficient wearing down of the brake lining. 